kmemleak: disable kasan instrumentation for kmemleak

kmalloc internally round up allocation size, and kmemleak uses rounded up
size as object's size.  This makes kasan to complain while kmemleak scans
memory or calculates of object's checksum.  The simplest solution here is
to disable kasan.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kmemleak.c

@@ -98,6 +98,7 @@
 #include <asm/processor.h>
 #include <linux/atomic.h>
 
+#include <linux/kasan.h>
 #include <linux/kmemcheck.h>
 #include <linux/kmemleak.h>
 #include <linux/memory_hotplug.h>
@@ -1113,7 +1114,10 @@ static bool update_checksum(struct kmemleak_object *object)
 	if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
 		return false;
 
+	kasan_disable_current();
 	object->checksum = crc32(0, (void *)object->pointer, object->size);
+	kasan_enable_current();
+
 	return object->checksum != old_csum;
 }
 
@@ -1164,7 +1168,9 @@ static void scan_block(void *_start, void *_end,
 						  BYTES_PER_POINTER))
 			continue;
 
+		kasan_disable_current();
 		pointer = *ptr;
+		kasan_enable_current();
 
 		object = find_and_get_object(pointer, 1);
 		if (!object)